Chicago-based FASA Corporation's original, 1984 BattleTech game focuses on enormous robotic, semi-humanoid battle machines called BattleDroids.[4] The name of the game was changed to BattleTech in the second edition because George Lucas and Lucasfilm claimed the rights to the term "droid"; the machines themselves were renamed BattleMechs from the second edition onwards. The visual design of the earliest line of BattleMechs were taken from Macross and other anime, including many signature images. In later years FASA abandoned these images, and it was common speculation by fans that the decision was the result of a lawsuit brought against them by Playmates and Harmony Gold [USA] over the use of said images.[5] No official broke the silence until 2007, after FASA had sold the BattleTech intellectual property to WizKids Games. Under license from them, the Classic BattleTech line developer for Fantasy Productions, Randall N. Bills explained that FASA had sued Playmates over the use of images owned by FASA, but received no compensation, even though Playmates was ordered to stop using the images in question. After realizing how the use of licensed images made them vulnerable to lawsuits and afraid that such a suit would bankrupt the company, FASA made the decision to only use images owned by them and them alone. The BattleMechs taken from the various anime sources were then considered "Unseen". When Fantasy Productions licensed the property, these "Unseen" images were expanded to include all art produced "out-of-house" – that is, whose copyrights resided with the creators, not the company. Catalyst Game Labs has continued this practice.[6] On 24 June 2009, Catalyst Game Labs announced that they had secured the rights to the "unseen"; as a result, art depicting the original 'Mechs absent from publications for over a decade, can be legally used again.[7] An update on 11 Aug. 2009 has placed the unseen restriction on several designs once again. This update affects only the designs whose images originated from Macross. Designs whose images originated from other anime such as Dougram and Crusher Joe are unaffected by this change and are still no longer considered unseen.[8] By August 2011, the remaining images that were considered to be unseen were returned to unseen status due to continuing problems with license agreements.[9]

At its most basic, the game of Battletech is played on a map sheet composed of hexagonal terrain tiles. The combat units are 30-foot-tall (9.1 m) humanoid armored combat units called BattleMechs, powered by fusion reactors, armed with a variety of weapons including lasers, particle projection cannons, autocannons, and both short and long range missiles. Typically these are represented on the game board by two-inch-tall miniature figurines that the players can paint to their own specifications, although older publications such as the 1st edition included small scale plastic models originally created for the Macross TV series, and the 2nd edition boxed set included small cardboard pictures (front and back images) that were set in rubber bases to represent the units. The game is played in turns, each of which represents 10 seconds of real time, with each turn composed of multiple phases. During each phase players alternate back and forth playing the game. The phases are initiative, movement, attack declaration, attacks, physical attacks, and end phase. Winning initiative actually means the winning player moves second, advantageous because the player can react to the movements and attack declarations of the losing player.

Heat buildup is a major limiting factor of the game, and overheating a unit can have many negative effects such as penalties to weapon accuracy, slower movement, catastrophic detonation of remaining ammunition or even the MechWarrior (the 'pilot' controlling the Mech)taking damage from the heat and baking to death.

Armor is tracked by body location of the mech, such as arms, legs, and multiple torso locations. Combat generally involves a slow attrition of damage over multiple turns of the game, although with some of the more powerful weapons carried by larger Mechs, combat can end quickly in under six turns (effectively one minute of real time).

The game's popularity spawned several variants and expansions to the core system, including CityTech which fleshed out urban operations, infantry and vehicle combat, AeroTech which focused on air- and space-based operations, and BattleSpace which detailed large spacecraft combat. FASA also published numerous sourcebooks that featured specifications for new combat units that players could select from. However, despite the large number of such pre-designed BattleMechs, vehicles, aerospace units and other military hardware, the creators also established a system of custom design rules, enabling players to generate their own units and field them in combat. This engineering aspect of the game, itself expanded by several design and technology sourcebooks, has proven to be enduringly popular and may explain BattleTech's longevity.

FASA launched two additional systems to complement the core game: BattleTroops, an infantry combat system, and BattleForce, a large-scale combat simulator governing the actions of grouped BattleTech units. The Succession Wars, a board game released in 1987, is one of only two purely strategic titles of the series (the other being "The Inner Sphere in Flames" from the Combat Operations book). The Succession Wars is played on a political star map, with players trying to capture regions of space.

Recent years have seen a trend of consolidating the expansions into the core products, beginning under FASA's aegis and continued by both FanPro and Catalyst Game Labs. Of the current set of core rules:[10]

Total Warfare (TW) integrates the basic elements of gameplay with CityTech and parts of AeroTech 2 (itself a consolidation of AeroTech and BattleSpace) pertaining to simplified atmospheric operations (such as landing the Dropship(s) onto a planet).

Tactical Operations (TO) supplements Total Warfare with optional Advanced Rules for planetary conquest, including an expanded weapons and equipment table (Lostech), as well as the use and construction of Large/Experimental units (consolidating Maximum Tech and other Sourcebooks, like Explorer Corps).

Strategic Operations (SO) consolidates optional rules for multi-game campaigns in a single star system (such as Unit Morale, Repair, Equipment Salvage, in-game Construction, and small economics) with the remaining AeroTech 2 rules (the usage and construction of large aerospace units: Jumpships / Warships / Space Stations / Fighter Squadrons; interstellar combat, and space-based operations), as well as a revised version of BattleForce.

TechManual (TM) consolidates the rules with minor Technical Fluff) for designing custom units compliant to Total Warfare / Competition rules from various products. (Tactical Operations supplements data for Advanced Unit construction, as TO is not usually Tournament Legal).

A fifth product, known as Interstellar Operations (IO?) is slated to introduce rules that control faction-wide operations(such as entire Clans / Succession Houses / Empires) and multiple campaigns that could span multiple star systems (up to and including the entire Inner Sphere).[11]

BattleMechs, the hulking flagship units of the franchise, made a natural subject for computer emulation, and so in 1988 Infocom released a PC based RPG called BattleTech: The Crescent Hawk's Inception, which took place in the canonized BattleTech story universe. It was later followed up with a sequel, BattleTech: The Crescent Hawk's Revenge in 1990. Both games were reasonably well received, although aside from storyline continuity the second game held few similarities to its predecessor.

The first pure simulation of BattleMech combat, however, was released for computers in 1989. Entitled MechWarrior and published by Activision, the single-player game gave users the opportunity to pilot a range of 'Mechs and engage in combat against computer-controlled opponents. Sequels MechWarrior 2 (1995), MechWarrior 3 (1999) and MechWarrior 4 (2000) created simulations of progressively higher technical sophistication. The most recent commercial game is MechWarrior 4: Mercenaries (2002) and the most recent developments have been in fan based modding. 'Mekpaks' for Mechwarrior 4 Mercenaries made by Mektek have been released, adding new Weapons, Mechs and graphics. A high Definition pack has been released for Mekpaks 2 and 3 by Mechstorm. Recently a group has been modding Crysis for the release of a BattleTech game known as MechWarrior Living Legends and the first public beta was released on December 26, 2009. A possible MechWarrior 5 was being produced, though it lingered in development for about a year and was eventually canceled. Currently Smith & Tinker own the MechWarrior Electronic franchise. As of July 9, 2009, it has been confirmed the franchise will be rebooted. Further trailers of MechWarrior Reboot were released and it was confirmed that the timeline would be reset to around 3015, several years before the start of the Fourth Succession War. Though it seemed that the legal troubles which originally plagued FASA due to the similarities between Battletech mechs and those in Robotech/Macross had returned to cause some troubles for Piranha Games,[14] the company later released a statement noting that their primary troubles had been with finding a publisher, which eventually lead to the announcement of a free-to-play reboot called Mechwarrior Online, set around the start of the clan invasions.[15]

A dedicated fan community also works hard on an online free version of the tabletop game, called MegaMek. This project led to follow up projects like MekWars, which aims at making campaigns out of MegaMek games. There were also a series of fan-created Battletech MUSEs then later MUXes (text-only multiplayer games with ASCII images, accessed by telnet connection) in the 1990s, starting with Battletech 3025 MUSE in 1991. As of 2014 the most active of the BTMuxes is Battletech: The Frontier Lands at frontiermux.com port 5555.

The BattleTech creators' goal of creating an immersive BattleMech simulation came to fruition in 1990 with the opening of the first BattleTech Center at the North Pier Mall in Chicago. The BattleTech Center featured 16 networked, full-sized cockpits or "pods" that resembled a fully functional BattleMech cockpit with over 80 separate controls. Each player selected a 'Mech to pilot into combat against up to seven other human players in the other cockpits.

Virtual World Entertainment, the company that managed the centers, later opened many other Virtual World centers around the world. It eventually merged with FASA Interactive Technologies (FIT) to form Virtual World Entertainment Group (VWEG) to better capitalize on various FASA properties. In 1999, Microsoft Corporation purchased VWEG to integrate FIT into Microsoft Game Studios and sold VWE. VWE continues to develop and support the current BattleTech VR platform called the Tesla II system, featuring BattleTech: Firestorm.

The popularity of the BattleTech games and the fictional universe they inhabit has led to a number of related projects in other areas. The most active of these is a line of popular science fiction novels, with more than 100 titles published to date. The novels are set in both the Classic BattleTech era (mid-3000s) and the Dark Age era (3130s). The original BattleTech novels were produced between 1986 until 2002; the Dark Age era Novels were produced from 2002 to early 2008. An online writing project named BattleCorps also produces novelettes set in various eras of the BattleTech universe.[16]

In July 2008 it was announced that both the Classic BattleTech and MechWarrior book lines would resume by the end of 2008.[17]

Electric Entertainment, a company under contract to Paramount Studios, has leased the rights to produce a motion picture based on the BattleTech universe, but development has been slow and little is known about the project's status.

As part of their line of BattleTech products, FASA printed The Spider and the Wolf in 1986, a comic-style sourcebook depicting the inception of the "Black Widow Company" in 3015 and offering a brief introduction to the BattleTech universe on the inside cover, and three game scenarios in the back of the book.

By virtue of being published by FASA proper, The Spider and the Wolf is considered canonical for the BattleTech universe, unlike other comics produced by third parties.

Blackthorne

In the late 80s, Blackthorne Publishing produced several licensed comics under the "BattleTech" moniker (including an "annual" and a 3-D issue), plus a series of "BattleForce" comics that was scheduled to run for (at least) three issues but had only two published, leaving the story arc unfinished.

The Blackthorne comics are not dated, but their time of publication and context suggests the stories are set in or around the year 3025, the "classic" period of BattleTech.

Malibu

A four issue comic BattleTech: Fallout was issued by Malibu Comics in 1994-1995,[18] plus a fifth issue (titled "Issue #0") that offered three very short stories supplementing the series, but outside of the story arc. Set during the Clan Invasion in early 3050, they depict disparate fugitives pairing with the Belt Pirates to form an irregular BattleMech force and end the Clan occupation of the Star's End system.

The first Fallout issue was also printed in two special editions, one with gold print ("gold edition") and one with a holographic cover.

A detailed timeline stretching from the late 20th century to the mid-32nd describes humanity's technological, social and political development and spread through space both in broad historical terms and through accounts of the lives of individuals who experienced and shaped that history.[19] Individual people remain largely unchanged from those of modern times, due in part to stretches of protracted interplanetary warfare during which technological progress slowed or even reversed. Cultural, political and social conventions vary considerably between worlds, but feudalism is widespread, with many states ruled by hereditary lords and other nobility, below which are numerous social classes.

A key feature of the BattleTech universe is the absence of non-human intelligent life. Despite one or two isolated encounters in novels, mankind is the only sentient species, making the incessant warfare among humanity's feudal empires seem a more realistic and direct extension of the past and present.

Above all, the central theme of BattleTech is conflict, something to be expected given the franchise's wargaming core.[1] Interstellar and civil wars, planetary battles, factionalization and infighting, as well as institutionalized combat in the shape of arena contests and duelling, form the grist of both novelized fiction and game backstories.

BattleTech's fictional history covers the approximately 1150 years from the end of the 20th century to the middle of the 32nd. Most works in the series are set during the early to middle decades of the 31st century, though a few publications concern earlier ages, including a technical readout describing 2750s-era technology.[20]MechWarrior: Dark Ages and its related novels take place in the mid 3100s.[21]

Because the BattleTech universe reached a pinnacle of scientific achievement before it collapsed in strife, there is an element of LosTech that is sometimes used as a tool in fiction and/or gameplay to add new dimensions to the storyline. LosTech represents designs and occasionally implementations of technological advances that were at some point achieved, but believed to have been lost over the ages. LosTech is frequently found in Star League-era caches, the locations of which have been forgotten or have been made inaccessible for various reasons. When designs and schematics are found, the most common source are old ComStar locations, as their organization held the majority of the most powerful and best-maintained computer systems.

Technological advancements occur throughout the history of the fictional BattleTech universe, which extends from the late 20th to mid-32nd centuries. The earliest published technical readout dates from the year 2750,[24] but the majority of such publications describe technologies as they exist in the 31st century. It's largely around this latter period that BattleTech centers.

One of the earliest and most significant events in BattleTech technology was the advent of faster-than-light travel, the principles of which were first described by Stanford University physicists Thomas Kearny and Takayoshi Fuchida in 2018. Scientists first successfully tested an FTL engine based on Kearny and Fuchida's work on 3 September 2107, and late the following year mounted the first long-range manned voyage, a 12-light year jump to the Tau Cetistar system. Though based on similar principles, faster-than-light communication in the form of Hyperpulse Generators wouldn't be developed until 2630.[25]

Technological advancements continued slowly but steadily through the third millennium, notably including the development of the first BattleMech by Terran Hegemony engineers in 2439.[26] This advancement reached its zenith during the latter years of the Star League with computing, communications, sensors, power and motor systems, medical sciences and other technologies reaching high levels of refinement.[24]

Following the collapse of the Star League in 2781, the league's constituent states fell into a protracted struggle for supremacy known as the The Succession Wars. The conflict saw the widespread destruction of factories, ship yards and research facilities, resulting in a slow but steady degradation of scientific and technological expertise. By the dawn of the fourth millennium, few sites in the Inner Sphere retained the ability to construct or even repair the more sophisticated Star League-era devices, and lost or hidden caches of such lost technology, or "lostech", became highly sought after. A mercenary unit, the Gray Death Legion, discovered one such cache, including a Star League memory core, on the planet Helm in 3026, a discovery that sparked a minor technological renaissance.[24]

The exodus of much of the Star League Defense Force after the league's collapse was also a significant blow to technological development in the Inner Sphere since it included many of the most advanced vessels and pieces of hardware. Later to become known as the Clans, these forces, unlike those in the Inner Sphere, generally retained a Star League level of technology, and though not advancing considerably beyond it over the following centuries, did make many refinements and enhancements that set them ahead of their Successor States counterparts. The return of the Clans to the Inner Sphere in 3048 prompted a flurry of technological development on both sides of the front, with numerous weapons and military systems quickly developed and deployed.[27][28]

In August 3132, a mysterious calamity collapsed the Hyperpulse Generator Network, inhibiting interstellar communication and heralding a slow-down of technological development.[citation needed]

Faster-than-light travel across interstellar distances is common in the BattleTech universe and depends on an advanced space-warping technology known as the Kearny-Fuchida Drive. Interplanetary and orbital space travel is also common practice, generally conducted by fusion-powered dropships and various smaller aerospace craft.

The theoretical underpinnings of the Kearny-Fuchida (or K-F) hyperspace drive originated in the early 21st century with Stanford physicists Thomas Kearny and Takayoshi Fuchida, whose experiments revealed that particles exposed to a hyperspace energy field jumped almost instantaneously between two points. Though originally dismissed, the effect was confirmed in the early 22nd century and a drive subsequently developed by the Terran Alliance to exploit the principle.

In a K-F jump, an initiator produces a hyperspace field which is then magnified and focused by a large, superconductive mass of titanium/germanium. The amplified field envelopes the ship and pushes it through a hole in normal space called a "jump point", through which it enters hyperspace. Depending on the distance to be traversed, the ship spends up to 15 seconds in hyperspace before reemerging into normal space through another jump point at the destination. The opening and closing of jump points destroys large numbers of subatomic particles and produces a pulse of electromagnetic energy that can be detected at considerable range.[29]

Jumps are normally made to and from points far above a solar system's ecliptic, usually where the gravitational influence in the system is most stable; however, so-called "pirate points" exist where local gravitational pull is stable enough to used; though quicker, using such points is also more dangerous due the random appearance of so-called "Lagrange points". Most Jumpship crews are left stranded in most cases of an emergency.[30]

Jumping requires copious amounts of energy, usually gathered from the nearby star over the course of approximately a week by large solar collectors similar to solar sails and stored in giant capacitors. Recent advances have dropped this to around 14 hours. A quicker but less common technique is to draw the energy from a fusion reactor, or to take advantage of recharge stations in the vicinity of major jump points.[30] Jump failures can result from charging the drive too quickly, poor drive maintenance or spatial anomalies.

BattleTech spacecraft range considerably in size and function, but generally fall into three broad categories – jumpships, dropships and small craft.

Vessels equipped with K-F drives are known as jumpships and range in mass up to 500,000 tonnes, though warships, a subclass of jumpship hardened against attack and fitted with naval weapons, may mass up to 2.5 million tonnes. The size and delicacy of a jumpship's K-F drive and the danger of jumping while in a gravitational well limits such vessels to deep space and precludes planetary landings. Jumpships often use sail-like collectors to gather solar energy and fusion engines for sub-light maneuvers, and normally travel with a small retinue of dropships.

Dropships are fusion-powered craft built to transport people and cargo between space-bound jumpships and planetary surfaces, or between jumpships. Dropships lack faster-than-light engines and instead use fusion motors for covering short interplanetary distances, for orbital and atmospheric maneuvers, and for takeoffs and landings. They mass anywhere between 400 and 100,000 tonnes, and are usually of either aerodyne (aerodynamic) or spheroidal configuration. Dropships in the BattleTech universe are used for both military and civilian/commercial transportation.

The smallest vessels capable of space travel are known simply as "small craft", or as aerospace craft if capable of planetary landings. They may serve military functions (as fighters or bombers) or civilian purposes (e.g., transportation).

HyperPulse Generator (HPG) arrays serve as the primary means of interstellar communication in the BattleTech universe and operate on worlds throughout inhabited space.

Developed by professor Cassie DeBurke, HPGs operate on a similar principal as the Kearny-Fuchida jump drive, sending a directional radio transmission instantaneously from one station to another over a distance of up to 50 light years.[25] Though the nature of the technology allows only unidirectional broadcasts, paired HPGs can provide simultaneous bidirectional communication. HPG stations are generally categorized as A, B, C or D: A stations, located on some 50 worlds throughout the Inner Sphere, have high volume capacity and transmit messages regularly, usually every 12 to 24 hours; B stations are present on most other Inner Sphere worlds and transmit every few days; C and D stations, more common on backwater worlds or in the Periphery, transmit less frequently. Given the demand and expense of hyperpulse communication, messages are frequently bundled into batches of hundreds, sent simultaneously. While the transmission itself is nearly instantaneous, it may be days, weeks, or months before a message is sent, though one can pay a higher fee for "priority service". A message can reach any station in the Inner Sphere in approximately six months, with transit times of as little as a few days possible at great expense.[31]

The first successful hyperpulse broadcast occurred on New Year's Day, 2630.[25] Over the next 150 years the Star League constructed a network of generators that extended hyperpulse communications to numerous worlds throughout the Inner Sphere. During the Succession Wars ComStar assumed the operation and maintenance of the network, shrouding the system's operation in mystical trappings. Though ostensibly neutral, ComStar leveraged its communications monopoly for political purposes, occasionally imposing "interdictions" (denials of service) on opposing organizations. Following the schism of the Word of Blake from ComStar after the battle of Tukayyid in 3052, hyperpulse technology slowly began to disseminate to the states of the Inner Sphere, with ComStar and the Word of Blake accepting money to fund the creation and operation of new stations. A mysterious calamity collapsed the Hyperpulse Generator Network in August 3132, effectively ending practical interstellar communication over much of inhabited space. In the wake of the collapse, jumpships served as a kind of "pony express", ferrying messages from world to world.

The most visible and distinctive machinery in the BattleTech franchise are the mecha known as 'Mechs. Those tailored for combat are known as BattleMechs and, with other less common forms such as WorkMechs and ProtoMechs, are central to BattleTech wargaming and feature prominently in most spinoffs and related fiction.

Neural engineering, particularly in the form brain-computer interfaces, is not uncommon in the BattleTech universe. Its principal application is the "neurohelmet", a device used in nearly all BattleMechs that gives the 'Mech's pilot the ability to control some aspects of the machine's behavior simply by thought. The neurohelmet provides balance information to the 'Mech to assist in walking and maneuvering. It also acts as a security device, limiting access to authorized users via alpha brain wave pattern recognition (many BattleMechs mentioned in the novels also incorporate more conventional security measures such as voice-recognition and personalised codes). Enhanced Imaging (EI) technology developed by the Clans uses a subdermal skein of wiring to grant better control over a machine.

More advanced neural engineering technologies include the experimental Direct Neural Interface (DNI), a system that provides a MechWarrior fuller mental control over a 'Mech than offered by a standard neurohelmet.[32] The system's potential for serious neurological damage to the MechWarrior prevented the technology from advancing beyond the prototype stage, though Vehicular Direct Neural Interface (VDNI) was later successfully deployed by the Word of Blake to create the "cyber-soldiers" of the Manei Domini.

Other applications of bionics range from prosthetic limbs, such as the hand of Justin Xiang,[32] to elective implants intended to improve strength or enhance the senses.[33] An extreme example of bionic augmentation was Captain-General Gerald Marik who in 2667 received extensive implants following a life-threatening injury.[34]

Created by Clan developers, OmniTech is a system of equipment modularization that allows key components of 'Mechs and vehicles to be easily mounted, swapped and replaced. "Omni units", as machines fielding the system are known, are built with standardized hardpoints and bays (called "pods") into which components are fitted. The system reduces repair time and allows units to be customized for varying missions.[35]

Little hard data exists on the nature and power of computer technology in the BattleTech universe, but what's been revealed suggests capabilities somewhat (but not radically) beyond that of today. The central DI computer of a 31st-century BattleMech automates the majority of the unit's functions, but lacks autonomy of action. Other BattleMech-mounted computers, designed for targeting or command and control, are massive by modern standards (from 500 kg to 3 metric tons), though how much of that mass is shielding or other supporting systems is unclear. More independent computers are said to have been used to control some Star League vessels, but at least one source suggests that the power and autonomy of some computers may be limited to prevent the possibility of danger should anything go wrong.[36]

Myomer, similar to modern electroactive polymers, is a fibrous material consisting of microscopically thin tubes filled with a substance (acti-strandular fiber) that contracts when voltage is applied and serves as artificial muscle in applications ranging from BattleMechs to artificial limbs.

Armor materials such as ceramic boron nitride, honeycombed titanium alloy, and "ferro-fiber", a resilient armor infused with diamond fiber. Armor in BattleTech is ablative in nature. This means that it is generally destroyed or blown off when hit, but in the process of doing so, it absorbs enormous energies, protecting the unit upon which it is mounted.

Structural materials such as endosteel, a form of endomorphic steel manufactured in zero-g with a foamed titanium core.

During prosperous eras of colonization, entrepreneurs employed jumpships to transport ice bergs from water-rich planets to arid colony worlds. Colonies dependent on this ice trade prospered while it continued, but little true terraforming was accomplished in this way and the colonies tended to wither when the trade was interrupted by wars. The practice was largely abandoned in the 27th century due to advances in water purification.[26]

Terraforming, the process of adapting an inhospitable planetary environment into one suitable for human occupation, occurs with varying degrees of success through BattleTech history. Terran engineers mounted repeated attempts over the course of centuries to moderate the dense and acidic atmosphere of Venus, succeeding enough to allow limited surface colonization under protective domes.

Terra is the homeworld of mankind (no longer commonly called Earth, although this name is sometimes used) and former capital of the Star League. Many planets around Terra were rendered uninhabitable during the first two Succession Wars, and surviving planets suffer from the damage even centuries later. Several dozen of these worlds, in what came to be known as the Chaos March, briefly gained their independence between 3057 and 3081. Historically, whichever faction controlled Terra has held more political power than any single Great House. Several groups have held Terra, including the Terran Alliance, Terran Hegemony, ComStar, Word of Blake, and Republic of the Sphere; most of these nations fought bitter struggles upon Terra, scarring the world.

The Inner Sphere, heart of the BattleTech Universe, contains all worlds within 500 light-years of Terra. It is dominated by five "Great Houses": House Davion, House Liao, House Marik, House Steiner and House Kurita. (The term "Inner Sphere" sometimes refers to these houses collectively). The leader of each Great House claims to be the rightful successor to the rule of the Star League, and so their nations are known as the Successor States.

There are few other significant nations in the Inner Sphere. The St. Ives Compact was a short-lived state that broke away from the Capellan Confederation after the Fourth Succession War, and was reabsorbed following a brief war in 3062. The Free Rasalhague Republic was created in 3034 by a deal between the Draconis Combine and the Lyran Commonwealth. It rivaled the Capellan Confederation for size, but by 3052 it had been almost entirely conquered by the Clans; in the 3070s, much of it was incorporated into the Ghost Bear Dominion (which is known as the Rasalhague Dominion by 3130). Similarly, the Federated Commonwealth was an alliance between the Federated Suns and the Lyran Commonwealth, resulting in the creation of a super Successor State that controlled over two fifths of the Inner Sphere.

The space surrounding the Inner Sphere contains a number of independent nations, known collectively as the Periphery. The largest of these nations (the Outworlds Alliance, Taurian Concordat, Magistracy of Canopus, and Rim Worlds Republic) predate the Star League and rival the Successor States themselves in size, but are inferior economically and militarily. More moderately sized nations, such as the Marian Hegemony or Bandit Kingdoms, also lie near the Inner Sphere. The Periphery contains countless other independent nations, many consisting of a single star system each and rarely playing a significant role in Inner Sphere politics. The mostly uncharted space beyond the nearby Periphery states is known as the Deep Periphery and contains numerous pirate havens and lost Star League colonies.

During the Fall of the aforementioned Star League, the Star League Defense Force exiled itself and eventually settled in the Deep Periphery. They reformed into the Clans, a warrior-centric caste society relying on genetic manipulation and artificial birth. The four strongest of these Clans returned to the Inner Sphere as would-be conquerors in 3049, were reinforced by three more Clans a year later, and were joined in the late 3060s by another two. Of the original twenty Clans, by 3067 three were absorbed, two were annihilated, two fragmented, two defected, and one was abjured. The Clan Occupation Zones together occupy a region roughly equivalent to one of the Successor States. [37]